BIOLOGICAL CLASSIFICATION OF GENERA. 



The following biological classification is introduced for the sake of convenience to 

 aid in quickly classifying any of the genera considered in the Bibliographic List. 

 Like the latter it includes only American Ordovician and Silurian genera. 



ANIMAL KINGDOM. 



Phyllum PORIFERA. 

 Class SPONGLE. 



Subclass SlLICISPONGLE. 



Order TETRACTINELLIDA. 

 Family ASTYLOSPGNGID^E Rauff. 



Astylospongia Roemer, Caryospongia Rauff, Caryomanon Rauff, Carpospongla Rauff, 

 Cyathospongia Hall, Carpomanoii Rauff, Palseomanon Rauff. 



Family HINDIID^E Rauff. 

 Hindia Duncan. 



Family ANOMOCLONELLID^ Rauff. 

 Anomoclonella Rauff, Pycnopegma Rauff. 



Family CHIASTOCLONELLID/E Rauff. 

 Chiastoclonella Rauff. 



Family AULOCOPID^E Rauff. 

 Aulocopella Rauff, Aulocopium Oswald, Dendroclonella Rauff. 



Family ARCH^OSCYPHID^: Rauff. 

 Archaeoscyphia Hinde. 



Family RHIZOMINNID^E Zittel. 

 Nipterella ninde. 



Family ANTHASPIDELLID^E Ulrich and Everett. 



Anthaspidella Uhich and Everett, Calathium Billings, Ch'macospongia Hinde, Edrio- 

 spongia Ulrich and Everett, Eospongia Billings, Strep tosolen Ulrich and Everett, 

 Streptospongia Ulrich, ?Trachyum Billings, Zittelella Ulrich and Everett. 



Family DYSTACTOSPONGID^E Miller. 



Dystactospongia Miller, Heterospongia Ulrich, Saccospongia Ulrich, Strotoepongia 

 Ulrich and Everett. 



Order HEXACTINELLIDA. 

 Family PROTOSPONGID^ Hinde. 



?Halichondrites Dawson and Hinde, ?Lasiothrix Dawson and Hinde, Phormosella 

 Hinde, Protospongia Salter, Stephanella Hinde. 



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